Displaying parent custom post type

Excellent plugin!!

I need to display the parent of the child on the current post using the shortcode in the side bar widget.

Parent cpt = “Portfolio”
Child cpt = “Trees”

My custom post type “Trees” has a parent custom post type “Portfolio”. Each of the “Trees” could have a different “Portfolio” post.

I have tried using this is in a side bar widget on the “Trees” post.

[display-posts post_type=”portfolio” post_parent=”current”] shows nothing

[display-posts post_type=”portfolio” post_child=”current”] displays all portfolio posts, but not jus the parent of this Tree.

Any help would be great. Thanks

http://wordpress.org/extend/plugins/display-posts-shortcode/